1. Field of Invention
The present invention relates to a circuit providing a voltage for a display. More particularly, the present invention relates to a circuit providing a common voltage for a panel of a display.
2. Description of Related Art
In a liquid crystal display (LCD), common voltages (VCOM) are usually provided to drive a panel and prevent material from aging, in which the common voltages can be separated into two types when applied, i.e. direct-current (DC) common voltages and alternating-current (AC) common voltages. Specifically, when the AC common voltages are applied, the AC common voltages with different voltage levels are alternatively generated to drive the panel.
However, the common voltages are required to be constant during the frame inversion of the liquid crystal display; that is, the common voltages have to be stable during the power saving operation of the liquid crystal display, so that the liquid crystal display can be successfully operated in the sleep or standby state. Therefore, problems may arise when the AC common voltages are applied during the power saving operation of the liquid crystal display.